Telephone system.



"s. LX'ANOCHOWSKI & H. E. HERSHEY.

TELEPHONE SYSTEM. A rucmon r |Lu'-ozc.5. ana.

' Pammd'se n 10,1918

3 SHEETS-SHEET 1.

4 5 a WWW 5 was AWN we R 5 m w? x 3 u m 9 6w l/V/TNESSJES' UNITED STATES PATENT OFFICE.

GEORGE A. YANOCHOWSKI, OF CHICAGO,

ILLINOIS, AND HARRY E. HERSHEY, 0]!

WHITE WATER, KANSAS, ASSIGNORS T0 AUTOMATIC ELECTRIC COMPANY, OF CHI- CAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Sept. 10, 1918.

Application filed December 5, 1913. Serial No. 804,894.

, To all whom it may concern:

Zens of the United States of America, and

residents of Chicago, Cook county, Illinois, and White Water, Butler county, Kansas, respectively, have invented certain "new and useful Improvements in Telephone Sytems, of which the following is 'a specification.

Our invention relatesto improvements in telephone systems, and it relates particularly to improved means for operating measured service devices or supervisory signals in automatic orsemiautomatic systems.

The object of our invention is to provide, in connection with a telephone system, a simplex circuitthat is, a circuit which includes two sides of the line in multiple with a ground return\ vhich circuit may be employed for either operating meters or paystation apparatus in automatic systems, or can be employed for supervisory purposes in semi-automatic systems. In these systems the talking current and operating impulses pass over the two sides of the line in series and thus the impulse or impulses which pass over the simplex circuit do not in any way interfere with the talking current or operating impulses;

A further feature of our invention is the provision of a ti1necontrolled mechanism associated with the simplex circuit for closing the same at predetermined time intervals, whereby a measured service device at the substation may be operated a number of times in accordance with the length of time any connection is established. Thus this timing mechanism can be regulated so as to operate every few seconds, and in that event the registering mechanism at the substation will accurately record the exact length of time of conversation and charges can be made accordingly, or, if desired, this timing mechanism can be so regulated as to close the simplex circuit once every three minutes, in which event the subscribers meter would be operated one step for every three minutes a connection is established.

A further feature of our invention relates to the application of this simplex circuit to a coin-co1lecting device, whereby a magnet is provided at the substation which is energized over this simplex circuit .to prevent conversation until a coin has been deposited.

These and other objects and features of our invention will be more clearly understood by reference to. the accompanymg drawings, in wluch we have illustrated our invention. in connection with automatic and manual apparatus of well-known types, although its application to other forms of automatic and semi-automatic systems will be readily apparent to those skilled in the art.

Figure 1 shows a subscribers substation A attached to a party-line, the line conductors of said party-line terminating in an individual or line switch C. The line switch shown at C is one of a grou of similar line switches the plunger (not 3 own) of which engage a shaft and are controlled by the operation of a master switch,- shown at D in such a manner that they are, when in lltll'l'llal position, held directly in front of the tern'iinals of a trunk line leading to a selector such as shown at E.

Fig. '2 shows a connector switch embodying the principles of our invention.

Fig. 3 shows a second connector switch adapted to be used in connection with our invention.

Fig. 4. shows a manual operators cord circuit for connecting a trunk line extending from the selector E with a trunk line extending to the connector J (Fig. 5).

Fig. 5 shows a subscribers substation A, together with a line switch C with which a connector J is shown connected.

For the purpose of supplying battery current for operating the apparatus and for talking purposes, there is shown a battery B, one terminal of which is grounded. The busy signaling machines Q, Q and Q as represented herein, comprise an induction coil or transformer, the primary winding of which is included ma local circuit with a battery and an interrupter. Through the medium of'this interrupter a current is sup-- vdenser 5. Being an automatic substation it is also provided with an automatic calling device which may be of the same type as that shown in British patent to S. G. S. Dicker No. 29,654 of 1910. At the substation A the calling device is shown diagrammatically by a pairof impulse springs 6 and 7 and a toothed impulse wheel 8, which latter is controlled by the subscriber through the medium of a dial (not Shown) provided with finger holes for convenience in turning. The Y switch-hook 9 controls a set of springs in such a manner that when the receiver is on the hook, the ringer 4; in series with the condenser 5 is bridged directly across the line, both sides of saidl-ine being opened beyond said bridge. When the receiver is removed from the hook, the springs assume a position in which the bridge above referred to is disengaged from one side of the line, and

- .set of springs in such a manner, that when when a proper coin is dropped inlhc slot,

it is at any other position but normal, the impedance coil 12 is disengaged from both sides of the line. For this reason it will be seen that the impedance coil 12 will not affectthe impulses delivered by the impulse springs 6 and 7.

The substation A is similar to the substation A, except that the magnet 10, instead of operating a counting mechanism, is arranged to control a set of springs in such a manner that when the magnet 10 is energized, a shunt is placed around the receiver 2 and the transmitter 3' is directly shortcircuited. Means are also m-orided so that the said springs are restored to normal.

The subscribers individual switch C is of the general type of subscribers switch shown in British patent to R. W; James No. 26,301 of 1906, being, however, of the particular type (llS('l(-EE(| in British patent to I T. G. Martin No. 1419 of 1910. This line the windings 25 and 39 is separatefrom that ofthe windings 11 and 26. The winding 25 operates both the plungeranin 27 and the armature 36, while the winding 39 is only strong enough to operate the cut-off armature 36 and to hold the plunger arm 27 in its operated position. \Vhen the plunger arm 27 is operated, the plunger is forced into a bank of contact springs,,lorcing the springs 28, 29, 30 and 31 into engagement with the springs 32, 33, 34 and 35, respec tively. Although only one set of springs to 35) is shown, each line switch is pro vided with a plurality of such sets, each set forming the terminal of a trunk line leading to a first-selector switch E. Each trunk line is connected in multiple with the .corresponding springs of all. the line switches of the group which is controlled by the master switch D. by the subscriber through the medium of the line relay 11, as will hereinafter be more fully explained.

The master switch I) is of the same general type as'that disclosed in British Patent No. 26,301 oi 1900, referred to above, being, however, of the particulai type disclosed in said British Patent No. 1419 of 1910.. The function of the master switch, as well known, is to maintain the plungers of all idle switches in position to engage the terminals of an idle trunk line.

The first selector switch E is of the gen eral type of selector switch disclosed in United States Letters Patent No. 815,321, granted March 13, 1906, to Keith, Erickson and Erickson, except that the so-called side switch is omitted, and its circuits are modi ficd to adapt the switch to operate in a system in which the impulses are delivered over the sides of the line in series. Among other details, the selector E comprises a bank of contacts arranged in horizontal rows or levels, which contacts are adapted to be engaged b a set of wipers 65, 66 and 67 carried 11 on a shaft (not shown) which has a ver ical movement controlled by the vertical magnet 50 and a rotary motion controllcd'by the rotary magnet 51. The operations of the switch are controlled through the medium of the double-wound line relay 40. Means for permitting the switch to be restored to normal position are provided in the release. magnet 121, which, upon energizing, withdraws the retaining pawls from the shaft. The springs 61 and 120 are permitted to close only when the switch shaft has been raised one or more steps from its lowest position. The relays 45 and 56 are slow acting relays, 0., they dce'nergize slowly after their energizing circuits are broken.

The connector switch I (Fig. 2) is of the generalv type of connector switch disclosed in United States Letters Patent No. 815,176, granted March 13, 1906, to Keith, Erickson. and Erickson, the circuits being modified, however, to adapt the switch to operate in a The switch I) is controlled,

system in which the impulses are delivered over the two sides of the line in series. The connector is provided with a shaft (not shown) carrying the wipers 89, 90 and 91, which shaft is controlled by the vertical magnet; 87 and the rotary magnet 99. The usual side switch comprising the wipers 88, 97, 98 and 99 is controlled by the private magnet 94- in the usual and well-known manner. The magi'iet 118 is the usual release magnet which, upon energizing, removes the retaining pawls from the shaft. .The springs 117 and 127 are permitted to 'close only when the switch shaft has been raised one or more steps from its lowest position. -The operations of the switch arecontrolled by the line relay 70, and the application of ringing current to the called line is controlled by the ringer relay 101. The relay 103 is the so-called back-bridge relay which feeds battery current to the called line. This relay controls the circuit of a pair of impedance coils which are adapted to be connected in bridge of the trunk line 71, 76. The battery B is adapted to be connected to this bridge, which battery connection is controlled by the slow acting relay 108, which in turn is controlled by the ring cut-off relay 104 in such a manner that battery is connected to this bridge for a short. interval of time when the subscriber responds, in a manner to be hereinafter more fully described.

The connector K (Fig. 3) is similar to the connector I (Fig. 2), except for the fact that the relay 208, which controls the bridge tl'irough theimpedance coils 209 and 213, which correspond in turn to the impedance coils 109 and 113 of the connector I, is controlled by a time mechanism M. This construction is such that the simplex circuit througl'i the coils 209 and 213 in parallel is closed intermittently by this time mechanism instead of being closed but a single time, as described in connection with the connector I. Y

The connector J is similar to the connector I, except that in place of the impedance coils 109 and 113 and the relay 108, this connector J is ')rovide(.l with a relay 30!) whose,

circuit is controlled by the back-bridge relay 303, which relay 309 in turn controls the circuit. of the impedance coil 313. This construction is such that when the backl'n'idge relay is energized, the relay 300 and impedance coil 313 are bridged across the conductors of the talking circuit and the ,battery B is connected to a mid point of this bridge and remains so connected until the baclcbridgc relaydeenergizes, in this manner distinguishing from the construction of the connectors I and K, in which the battery was connected to this bridge only lIlOIIlGIlttlI'llYu The cord circuit G (Fig. 4) is a well known type of cord circuit, comprising the usual answering, and calling plugs I and P, respectively, inductively connected together through the medium of the condensers 159 and 171. The usual supervisory lamps 157 and 160 are controlled by the well-known plug seat switches shown at 156 and 158. The key L is a listening key for connecting the opcratofis talking set. with the cord (i. The key L is a calling device key, the purpose of which is to connect a calling device with the cord circuit, through the 'medium of which the operator may control the automatic switches to set up the proper connection. The calling device may be of any desired type, such. for instance, as that shown in British Patent No. 29,054 of 1910, above referred to,

through the medium of which calling device the operator may interrupt the bridge across the trunk line a desired number of times for each of the digits of the number of the called subscriber.

Having given a general description of the apparatus, it will now be explained how a. subscriber, such as the subscriber A, may es tablish connection with various subscribers who are accessible first, through the connector I and then through the connector K. The connector I, for example, can be considered one which has access to local subscribers, as when connection is made throu h this connector, the meter of the calling su scribers line is operated but a single time for each call. The connect-or K can be considered one which has access to subscribers at a. more distant ,point, and when connection is establishedthrough such connector, the subscribers meter is operated once for every predetermined period during which the connection is established.

Since the automatic switching apparatus disclosed is of a well-known type and is in general well known in the art,'and is fully described in the patents and publications referred to, it is not thought necessary to describe the operations in detail, but their operations will be described in a more or less general manner. I

1" hen the subscriber'at substation A removes his receiver from the switch-hook preparatory to making acall, the line winding 11 of the line switch C is closed in the well-known manner, and this line switch is then operated to connect with an idle trunk line exteiiding to the selector E. This operation is well understood and is fully described in the British patents referred 'to, and it is accordingly thought unnecessary to describe its operation further. Upon this line switch seizing an idle trunk line, which we will assume tube the trunk line 32, 35, the line relay 10 of theselector E is :energized over the following circuit: from ground G through the lower half ofthe line relay 40., springs 41 and 42 of the relay 68, springs 35 and 31, line conductor 15, springs 16 and 17 at the substation A, receiver 2, impulse springs 6 and 7, transmitter 3, springs 18 and 19, line conductor 20, springs 28 and-32, springs 43 and 44 of the relay 68 and the upper winding of the line relay 40- to' battery B. A branch circuit at the substation A is formed from the spring 17 through the springs impedance coil 12 and the springs 24 to the spring 18. A circuit may also be traced from ground G through the relay 10, left-hand half of the impedance coil 12, springs 24, springs 18 and 19, line conductor 20, springs 28 and 32, springs 43 and 4 1 of the relay (SS'and the upper winding of the relay 4-0 to battery B. The resistance of this circuit is sufficient to prevent the relay 10 from operative] y energizing at this time. The line relay it), upon becoming energized over the above circuits, closes a circuit through the relay 45 from. ground G through the springs i6 and -17 and the relay 45 to battery B. The relay 45, upon beconiing energized, forms the holding circuit for the switch (1, which circuit extends from ground through the springs 48, springs 33 and 29 and the holding Winding 39 to battery B. The winding 39, upon energizing, holds'the arn'iature 36 and the plunger arm-27 in their operated positions after the circuit of the pull-in winding 25 is broken by the falling back of the armature 37. From the spring 29 a guarding potential is extended by the conductor 49- to the private bank contacts associated with the line switch G. The energization of the relay 45 also prepares a circuit for the vertical magnet 50 by bringing into engagement the springs 5i and and opens the circuit of the release magnet 121 at the springs 54: and 119.

The calling subscriber now operates his calling device for the first digit 2 of the called number. It will readily be seen that the impedance coil 12, which was heretofore bridged across the line, is cut off at the springs 23 and the springs 24 at the instant that the dial is rotated by the subscriber, and that said impeda ce coil will not again be bridged across the line until. all the impulses for the digit have been delivered. The substation impulse springs (5 and 7 are twice momentarily separated, each time breaking the circuit of the selector line relay 40. The relay 45 of the selector E being slow acting does not deenergize during the momentary interruptions of its circuit by the relay 40 and consequently, each time the latter relay deiinergizes, an impulse is transmitted over a circuit extending from ground G through the springs 46 and 52, springs 53, springs 51 and 55, relay 56 and the vertical magnet 50 to battery B. The ver tical magnet receives tWo impulses over this over the contacts circuit and operates to raise the switch shaft and wipers tWo steps to a position opposite the second row or level of bank contacts. The slow acting relay 56 is maintained in its energized position continuously While impulses are being transmitted to the ver tical magnet through it, and in its energized position closes a circuit extending from ground G through the springs 57 and 58 and the relay 59 to battery B. Thenrelay 59, upon energizing, forms a locking circuit foritself extending from ground G through the springs 48, springs 60, ofl normal springs 61, springs 62 and 63 and the relay 5-9 to battery B. Thus upon the denergization of the relay 56 after the last impulse is delivered to the vertical magnet, the relay 59 remains energized and the circuit of the rotary magnet. 51 is closed, Which circuit extends from. ground G through the springs 4-8, springs (30, off-normal springs 61, springs 62 and 63*, springs 58 and 63, springs 64 and the rotary magnet 51 to battery B. The rotary magnet, upon, energizing, rotates the Wipers one step and, by opening the springs and the springs 0%, disconnects ground (i from itself and the relay 59. If the first trunk line of the second level is idle, the relay 59 deenergizes as soon as the springs 60 are opened. If this trunk line is busy, however, the private Wiper 66 finds the contact which it engages provided with a guarding ground potential which is transmitted tl'irough the springs 62 and 63 of the relay 59 and prevents the'relay 59 from deenergizing. The magnet 51, how ever, deei'iergizes when the springs 64 are broken, regardless ofwhether or not the relay 59 remains energized. If the relay 59 remains energized, the circuit of the rotary magnet will be again closed as soon as its armature drops bacltfar enough to close the springs 64-. The rotary magnet will, therefore, operate in a manner similar-"to that of a buzzer to advance the Wipers step by step until the non-grounded contact of an idle trunk is reached by the Wiper 66, whereupon the relay 59 d'energizes. The relay 59, upon deenergizing, whether' after one or several operations of the rotarv magnet, permanently breaks the circuit of said rotary magnet and closes the circuit of the switching relay 68, Which circuit extends from ground Gr through the springs 4.8, springs 60, ofi'-normal springs 61, springs 62 and 69 and the relay 68 to battery B. The relay disconnects the line relay 40 from the line vvipers65 and 67 to the connector I. The line relay 70-of' the connector I becomes engerized over a circuit extendin from ground G through the lower Winding of the relay 70, conductor 71, bank contact 72, line wiper 67, springs 73 and 42 of'the (38, upon. energizing,

and extends the line connection through the lay -15. ground G through the springs 80, conductor 81, bank contact 82,

relay 68, springs 35 and 31, 'line conductor 15, springs 16 and 17 of the substation A, receiver 2, impluse springs 6 and 7, transmitter 3, spring 18 and 19, line conductor 20, springs 28 and 32, springs 43 and 74 of the relay 68, line wiper 65, bank contact 75, conductor 76 and the upper winding of the line relay to battery B. At the substation A a branch circuit is formed from the spring 17 through the springs 23, impedance coil 12 and the springs 24 to the springs 18. A circuit may also be traced from ground Gr through the relay 10, left hand half of the impedance coil 12, springs 24, springs 18 and 19, line conductor 20, springs 28 and 32, springs 43 and 74 of the relay 68, line wiper 65, bank-contact 75, conductor 76 and the upper winding of the line relay 70 to battery 13. The resistance of this circuit is sufficient to prevent the relay 10 from operatively energizing at this time. The energization of the line relay 70 closes a circuit through the relay 77 from ground (:r through the springs 78 and 79 and the relay 77 to battery B. The energization of the relay 77 affords a new holding ground for the relay 68 of the selector E and the holding winding 39 of the line switch C to take the place of ground G which is removed upon the deenergization of the re- This holding circuit extends from private wiper 66, Springs 62 and 69 and the relay 68 to battery A branch of this circuit also extends from the private wiper 66 through the offnorrnal' springs 61, springs 60, springs 33 and 29 and the holding coil 39 to battery B. From the spring 29 the conductor 49 carries the guarding potential to the connector private bank contacts associated with the line switch C. The energization of the relay 77 also prepares the circuitof the vertical magnet 87 at the springs 81 and 85 and opens the circuit of the release magnet 118 at the springs Standgllfi. "Vhen the substation calling device is second digit 2, the circuit line relay 70 is broken twice. Since the rclay 77 is slow acting itdoes not deiinergize during the momentary interruptions of its circuit by the line relay 70, so that each time the latter relay is dei ncrgized; a circuit is closed extending from ground G through the springs 78 and8fl springs 84 and 85, relav 86, vertical magnet S7and the side switch wiper (in first position) to battery B. The vertical magnet receives two impulses over this circuit and operates to raise the switch shaft an'd wipers 89, 60 and 91 to a position opposite the second level of bank contacts. Therelay 86, which is of the connector included in the operating circuit of the vertical H'HIgHL'i IGIHtLJI'IH in position during the entire time its energized that impulses operated for the are being transmitted through it and operates to close the circuit of the private magnet 94. from ground G through the springs 92 and 93 and the private magnet 94 to battery B. After the last impulse has been delivered, the relay 86 opens the circuit of the private magnet 94, which, upon de'c'nergizing, permits the side switch to pass from first to second position. The movement of the side switch wiper 88 from first to second position transfers the battery connection from the vertical magnet to the rotary magnet.

The calling subscriber now operates his calling device for the last digit 2, in response to which the connector line relay 70 operates to tran mit two impulses through the rotary magnet 96 in series with the relay 86 over a circuit extending from ground G through the springs 78 and 83, springs 84: and 85, relay 86, springs 95, rotary magnet 96 and the side switch wiper 88 (in second position) to battery B. The rotary magnet thereupon rotates the shaft wipers onto the contacts of the called line, which called line we will assume is similar to the line to which the substation is connected and is provided with a line switch similar to the switch C. Therclav 86 operates in response to the impulses for this digit in the same manner as for the previous digit to cause the private magnet 04 to advance the side switch to third position. By the engagement. of the side switch wipers 97 and 98 with their third-position contact points, the line connection is completed with the called line. Upon the engagement of the wiper 99 with its third-position contact point. a circuit is completed through the cutoff winding of the called liuc switch. The said circuit extends from ground ti through the side switch \vipcr H9 (in. third position). private wipcr 9i) and the cut-ofl" winding of the called line switch to battery B. The cutoli' winding oi lhc .callrd line switch, upon energizing. operates to disconnect the line relay from the callcd substation. The connection of ground U with the connector banlccontact of the called line prevents the called line from being seized by some other connector switch. lly the cngagcincntot the. side switch wipcr 88 with its thirdposition contact point, ihc circuu of the ringer relay 101 is closed. This circuit extends from ground (i"-' through the interrupter 100, ringer relay llll. springs 102 and the side switch wipcr 88 (in third position) to battcry ll. The ringer relay disconnects the calling line from the called line and bridges the ringing current generator R across the called line to signal the called subscriber. 'lhc ringer relay is energized only..intermittcntly through the medium of the interru )tcr 100. Upon the response of the called filll iscl'ilwl his, line is n'orided with talking current through the windings of the backbridge relay ,103, which relay, upon energizing, closes a circuit through the ringer cut-off relay 101, the circuit extending from ground G through the side switch wiper 99 (in third pOSlt10ni, S )rings 100 and the relay 104 to battery B. 'herelay 104-, upon energizing, interrupts the circuit of the ringing relay-at the springs 102 and. closes 10 a locking circuit for itself through the springs 105 independent ofthe springs 106. The instant that the side switch passes to third position a circuit is closed through the slow acting relay 108 as follows: from ground G through the side switch wiper 99 (in third position), springs 107 and the relay 108 to battery B. The relay 108, upon energizing, connects the coils 109 and 113 in series and connects battery B with a point between them. The back-bridge relay 103 being energized :it this time, these coils 109 and 113 are bridged across the conductors oi. the talking; circuit. circuit therefore closed from battery B. contact prings 115, 112 and 110. through the coils 109 and 113 in parallel, thence over the two sides of the talking; circuit in parallel to the calling substation A, thence through the coils 12 to their mid point and then through the relay 10 to ground G Sutiicient current flows over this paralle circuit to cause the relay 10 to energize and it therefore operates to advance the counting mechanism one step. It will be seen that when the ring cut-off relay 104 energizes. the circuit of the relay 108 is broken at the springs 07. The relay 108 made slow acting so that it may reinain energized ong enough to send an' impuse of current over the. simplex-circuit sufficient to operate the meter at the substation A. Upon the dcenergization 01 1118 relay 108 the simplex circuit is broken at the springs 110, 112 and 115 and therelay 10 at the substation A returns to normal.

After the conversation completed, the connection is released by the hanging up of the receiver at the calling substation in the usual and well-known manner, which it is not thought necessary to here describe in detail.

It the called line had been busy when the connector wipers landed on the bank con tacts of the called line, then the side switch would not have passed tothird po- 5 sition and connection therefore would not have been established with the called line.

The busy machine Q, would also have been connected with the. calling line. all in a manner well understood in the art. The calling subscriber, upon hearing the busy. signal. replaces the receiver upon the hook, whereupon the switches are released in the regular manner.

Should, now, the subscriber whieh is indicated at K.

to battery B.

at substation A wish to establish connection with-willie which is accessible from the connector K (Fig. he would proceed in the same manner as above outlines, except that he would operate his calling dial for a first digit 3 instead of thereby raising the first selector tothe third level of bank contacts which are connected to a group of connectors, one of Upon the subscriber at. the substation A. callingthe last two digits of the called number, the action of the connector K is the same as explained for the connector I, except that as soon as the side switch 288 passes to third position, a circuit is closed through the relay 208, said circuit extending from ground through the relay 208 and the side switch wiper 288 (in third position) to battery B. By means of clockwork M the ground connection to the relay 208 is broken at regular intervals of time. 'hen the back-bridge relay 203 becomes energized, due to the called subscriber removing his receiver, the coils 200 and 213 are connected one to each side of the calling line in the same manner as is described in connection with the coils 109 and 1.13 of the c'onm-ctor 1. Each time the mechanism M ompletes the circuit. of the relay 208, the springs 210, and will be closed, thus completing the circuit between the coil 209 and the coil 213 and placing battery B between them. substation A is energized over the simplex circuit and causes the counting mechanism to advance one step for each impulse sent out from the mechanism M. In this way the meter at the substation A will be ope 'ated in proportion to the lengtho" time that the subscriber at the substation A converses with the called subscriber, instead of being operated but once. as in connection with the connector 1 It, now. the subscriber at the substation A wishes to extend a. connection through the manual board L. he proceeds as heretofore described. except that he operates his calling dial for a first digit. 1, whereby the selector E is raised to the first level from which extend trunk lines to the manual board L. each of which trunk lines includes a group of re lays I. lVhen the selector thus extends a connection to the group of relays F. a circuit may be traced from ground G through the coil H1. springs 142 and H3. conductor 110, bank contact137, linewiper 07 to and through the substation A, over the circuit previously traced and back to the line wiper 65, through the bank contact 135. conductor 138, springs It) and 111 and the relay 146 The relay H6, upon energizinc, forms aholding'. circuit for the relay 68 of the selector l) and the holding winding 30 of the line switch from ground G through the springs HT. conductor 139, bank contact 136, prirate wiper (i6 and continuing over the circuit previously traced to bat- As a result the relay 10 at the its tery B. The energization of the relay 146 also closes a circuit through the lamp 149 as follows: from ground G through springs 148 and the lamp 149 to battery B. The op- 5 orator, upon seeing the lamp 149 lighted, plugs into the jack N with the answering plug I. The engagement of the sleeve of the plug I with the bush of the jack N closes a circuit through the cut-off relay 150. The cut-oft relay, upon energizing, cuts off the relay 146 and the coil 141 and extends the lines to the cord circuit G. A circuit may now be traced from ground G through the relay 151, ring of the plug P and ring spring of the jack X, springs 152 and 143, conductor 140 to and through the substation A, over the circuit previously traced and back to the conductor 138, Springs 145 and 153, tip spring of the jack N and tip of the plug T and the coil 15% to battery B. The tip of the plug P also forces the springs 155 into engagement. which connects ground G" in the holding circuit for the relay 68 of the selector E and the holding coil 39 of the line switch (1 before traced. The relay 146 is made slow acting so. that ground G" will not be removed until time has been given for the plug l to be forced clear into the jack X. hen the plug 1 was removed from the 30 plug seat witch 156. the lamp 157 was li hted. The lamp went out. however, as soon as the relay 151. was energized. The operator will now depress [lei-listening key and converse with the subscriber at the sub-- station A. Upon learning that he desires connection with the substation A, the numher of which we will assume to be 22, the operator removes the plug P from the plug seat switch 158 and touches the tip of said plug to the bush ot' the outgoing jack II. If a multiple of the jack ll be busy. or should a selector have seized that trunk. the hush will have a guarding potential upon it which will give the operator :1 click in her receiver when she places the tip ot the plug 1" against the hush. due to the discharge of the condenser 15%. .\Hsulllillg that the trunk to which the jack. ll is connected is idlcgthe operator then forces the plug 1" into the jack ll. which extends the line connection to the connector J over the conductors 16; and

164. Immediately the connector 1 returns a guarding ground ovcr the conductor 16:; to the bush ol the jack ll. l pon removing the plug? from the plug seat switch 158, the lamp 166 is lighted and rcmalns lighted until the called subscriber answers. The operator now operates the key L to bridge hcr calling device llil across the conductors 16; and 164. She thou operates hcr calling dcvice for the digit'. twice. as a result of which um connector .I operates to cxtcnd the connection to the called substation exact l v as (xilained in the description of the connector I. The operator-now restores the key L to normal, bridging the relay 165 across the conductors 162 and 164. The resistance and construction of the relay 165 is such that it will not operatively energize with the current received through the connector line relay 370, although the said connector line re- .13 is connected to a point between the relay 312 and the coil 313. As a result, current will flow from ground G through both windings of the relay 165. both sides of the line in parallel and the relay 309 in parallel with the coil 313 to battery B. The relay 165 will be energized over the above circuit, thus opening the circuit of the lamp 160 at the springs 166. The extinguishing of the lamp 166 notifies the operator that the called subscriber has answered. whereupon the operator depresses the key L which sends an impulse t irough the impedance coil 167 over the simplex circuit previously traced to operate the meter at the substation A.

lVhen the conversation is completed and the calling subscriber hangs his receiver upon the switchhook, the circuit through the relay 151 is broken. The relay 151, upon dci ncrgizing, again closes the circuit of the lamp 157. \Vhen the called subscriber replaces his receiver upon the switchhook. the circuit of the back-bridge relay 303 is broken. The dci nergization of the relay 363 removes the relay 309 and the relay 313 from across the line. This causes the relay 165 to dei ncrgize and again light the lamp 160. The operator. noticing the lamps 157 and 166 glowing, knows that the conversation has been completed and reniovcs the plugs l and P from their respective jacks N and ll. The removal of the plug l takes ground from the relay 68 and the holding coil-36, whereupon the release of the selector F. and the line switch 'l'ollows. in the manner well undcrstoml in the art. The removal of the plug 1." from the jack ll likewise causes the connector J to release.

At. the suhstation (Fig. 5) we have shown a modil'icd arrangement in which the magnet 10', instead of operating a registering or counting mechanism. as does the magnet 10 in Fig. 1. controls a coin-coin trolled mechanism. This magnet it) is connected in the simplex circuitin' the same manner as is the magnet 16. heretofore dcseribcd. Accordingly, when the subscriber A extends a connection through a connector, such as the connector J this magnet 10 is included in the simplex circuit assoon as the back-bridge relay 303 of the connector J is operated, in the manner heretofore described. This magnet 10, upon operating, closes a short-circuit around the transmitter 33' and a shunt circuit around the receiver 2. As a result, the subscriber at the substation A can hear the called subscriber answer, but will be unable. to converse with him either through the trans mittei' or the receiver. Thereupon the subscriber at the substation A deposits a coin in the slot, said coineausing the arm 168 to befreed from the armature 169. The freeing of the arm 168 removes the shunt from the receiver 2' and the short-circuit from the transmitter 3' even though the re lay 10 remains energized, thus allowing the subscribers to converse.

It will thus be seen that we have devised a Very eilicient system in which a simplex circuit can be employed for operating varying forms of measured service devices or for supervisory purposes. lVhile for the purpose of illustration and to more fully describe the application of our invention. we have shown the same in connection with automatic apparatus of well-known types, i will readily be apparent to those skillcd inthe art that our invention is equally as well adapted for use in connection with many other forms of automatic apparatus.- Likewise, the particular form of manual apparatus shown in Fig. 4- could be modified to suit varying requirements.

Vhat we claim as our invention is 1. In a telephone system, a plurality of subscribers lines, means including automatic switches for cstahlishing a talking circuit between two oi said lines, said talking circuit including a pair of talking conductors, means ("ontrolhal by the response f the. called subscriber for closing a cuit including the. two sides oi said talking circuit in parallel, and a measured service device controlled over said circuit! 2. In a telephone system, a plurality of subscribers lines, means including automatic switches for cstablishing a talking circuit bctween two of said lines, said talking circuit including a pair of talking conductors, means controlled by the response of the called subscriber for closing a circuit including the two sides of said talking circuit in parallel, and a coin-controlled device controlled over said circuit.

3. In a telephone. system, a plurality of subscribers lines, means including automatic. switches for establishing a talking circuit between two of said lines, said talking circuit including a pair of talking conductors, means controlled by the response of the called subscriber for closing a.circuit gizmg circuit of battery to n.ectcd from the mid including the two sides of said talking circuit in parallel, and a counting or registering mechanisn'i controlled over said circuit.

4. In a. telephone system, a plurality of normally disconncctial subscribers lines, means for establishing connection between two of said lines, a bridge across the calling line and individual thereto, a magnet connected from the mid point of said bridge to ground, a second bridge adapted to be placed across the conductors of the talking circuit, and means controlled by the response of the called subscriber for automatically coi'mccting battery to a mid point of said second bridge to thereby close an enerthrough said magnet, and a measured service device controlled by said magnet.

5. In a telephone system, a. plurality of normally disconnected SllbSCIlbOlS lines, means for establishing connection between two of said lines, a bridge across, the calling line and individual thereto, a magnet connected from the mid point of said bridge to groum'l, a second bridge adapted to be placed across the conductors of the talking circuit, a battery adapted to be connected to said second bridge, and means controlled by the response of the called subscriber for closing said second bridge to thereby cause the operation ot'saidmagnet, and a. measured service device controlled by said magnet.

(S. In a telephone system, a plurality of normally disconnected subscribers lines, means for establishing connection between two of said lines, a. bridge across the calling line and individual thereto, a magnet con nccted from the mid point of said bridge to ound, a second bridge adapted to be placed across the conductors 01 the talking circuit, a battery EUl'LLPtPd to be connected to said second bridge, means controlled by the rcsponsc oi lhc called subscriber for closing said second bridge to thereby causethc operation of said magnet, a'measured service device controlled by said magnet, and means forintermiltci t breaking the connection l second bridge.

7.- In a telephone system, a plurality of normally disconnected subscribers lines, means for establishing connection between two of said lines, a bridge across the calling line and individual thereto, a magnet conpoint of said bridge to second bridge adapted to be placed across the conductors of the talking circuit, means controlled by the response of the called subscriber for closing said second bridge to thereby cause the operation of said magnet, a measured service device controlled by said magnet, and means for momentarily connectingbattery to said second bridge.

8. In atelephone'system, a plurality of ground, a

subscriberslines, means including automatic switches for establishing a talking circuit between two of said lines, said talking circuit including a pair of talking conductors, electromagnetic means controlled b the response of the called subscriber for cl bsing a circuit including the two sides of said talking circuit in parallel, and a measured service device controlled over said 'circuit 9. In a telephone system, a plurality of subscribers lines, means lncluding automatic switches for establishing a talkin circircuit including a pair of ta king conductors, electroma netic means controlled by the response 0 the called subscriber for closing a circuit including the two sides of said .talking circuit in parallel, and a coincontrolled device controlled over said circuit.

10. In a telephone system, a plurality of c'uit between-two of said linesf said ta king subscribers lines, means including automatic switches for establishing a talkin circuit between two of said lines, said tal ing circuit including a pair of talking conductors, electromagnetic means controlled by the response of the called subscriber for closing a circuit including the two sides of said talking circuit in parallel, and a counting or registering mechanism controlled over said circuit.

11. In-a telephone system, a lurality of normally disconnected subscri ers lines, means including automatic switches for es tablishing a talkin circuit between two of 'said lines, said tal ing circuit including a pair of talking conductors, means controlled by the response of the called subscriber for closing a circuit includingthe two sides of said talking circuit in parallel, mechanical means controlled over said circuit, and a pay station device controlled by said mechanical means,

12. Ina telephone system, a lurality of normally disconnected subscribers llnes, electromagnetic'means for establishin connectiombetween two of said lines, a bridge across the calling line and individual thereto, a ma et connected from the mid point of said ridge toground, a second bridge adapted to be placed across the conductors magnet, and a meter controlled of t e talking circuit, electroma netic means for automatically connecting attery to a mid 'pointof said second bridge to thereby close an energizing circuit through said y said magnet.

13. In a telephone system,;a plurality of normally disconnected subscribers hnes,

electromagnetic means for establishin con- :nection between two of said lines, a ridge across the calling line and individual thereto,'ama t connected from the mid point of' said ridge to ground, a second bridge ada )ted to be placed across the conductors of t lie talking circuit, a batter adapted to be connected to said second brldge, electromagnetic means controlled by the res )onse of the called subscriber for closing'sai second bridge to thereby cause the operation of said magnet, and a coin collecting device controlled by said magnet.

14. In a telephone system, a )lurality of normally disconnected subscri ers llnes, electromagnetic means for establishin con nection between two of said lines, a ridge across the calling line and individual thereto, a magnet connected from the mid point of said bridge to ground, a second bridge adapted to be placed across the conductors of the talking circuit, a battery adapted to be connected to said second brldge, electromagnetic means controlled by the response of the called subscriber for closing said second bridge to thereby cause the operation of said magnet, electromagnetic means for intermittently breakin the connection of battery to said secondiridge, and a measured service device controlled by said magnet,

15. In a telephone system, a plurality of normally disconnected subscribers llnes, electromagnetic means for establishing connection between two of said lines, a bridge across the calling line and individual there'- to, a magnet connected from the mid point of said bridge to ground, a second bridge adapted to be placed across the conductors of the talking circuit, electromagnetic means controlled by the response of the called subscriber for closing said second bridge to thereby cause the operation of said magnet, and electromagnetic means for momentarily connecting battery to said second brid e, and a measured service device controlled y said magnet.

16. In a telephone system, a plurality of normally disconnected subscribers lines, a meter on one of said lines, automatic progressively movable switches for connecting two of said lines, a bridge across the calling line, a'magnot connected from the mid-point of said bridge toground, a second bridge adapted to be placed across the conductors of the talking circuit, and means for automaticallyconnecti battery to a mid-point" of said second bri ge to thereby close an energizing circuit through said magnet for controlling said meter.

17. In a telephone system, a plurality of normally disconnected subscribers lines, a measured service device on one of said lines, automatic progressively movable switches for connectm two of'said lines, a bridge across the cal ing line, a magnet connected from the mid-point of said bridge to round, a second bridge adapted to be place across the conductors of the talking c1rcuit, a battery adapted to be connected to said second bridge, and means controlled by the response of the called subscriber for closing said second bridge to thereby cause the operation of said magnet for controlling said measured service device,

18. In a telephone system, a plurality of normally disconnected subscribers lines, a measured service device on one of said lines,

'automaticl progressively movable switches for connectln' two of said lines, a bridge across the 'cal'ing line, a ma net connected from mid-pointof said bri ge to "round, a second bridge adapted to be placer. across the conductors of the talking circuit, a battery adapted to be connected to said second bridge, means controlled by the response of the called subscriber for closing said second bridge to thereby cause the operation of said magnet for controlling said measured service device, and means for intermittently breaking the connection of battery to said second bridge.

19. In a telephone system, a plurality of normally disconnected subscribers lines, a coin coiiecting device on one of said lines, automatic progressively movable switches for connecting two of said lines, abridge ucross the calling line, a magnet connected from the midpoint of said bridge to ground. a second bridge adapted to be placed across the conductors of the talking circuit, electromagnetic means for automatically obnnccting battery to a mid-point of said second bridge to thereby close an energizing circuit through said magnet for controlling said coin collecting device.

Signed by us at Chicago, Illinois, this 25th day of. November, 1913 GEORGE A. YANOCHOVVSKI. HARRY E. HERSHEY.

\Vitnesses H. W. 1(RAGKE, B. GARRY-1R, 

